Recovering from disk damage after a system hang. Newbie question.

[Bob Cahn]

My system froze.  The mouse didn't move.  All apps were unavailable. 
Eventually I hit the big red switch and when the system started
rebooting I asked for the integrity check on the disks.  That came back
with problems and aborted the reboot so I finally just allowed the
system to reboot.  All seems normal but I think I still need to run a
disk check to see what damage was done.  All disks are ext3. What
programs (since I assume there must be several) can I use to check the
system integrity?

/Bob Cahn